Surging and BST

[Craig McGoo]

Hello all,

Having a strange issue with my NS. Most annoying one is the issue of negitive BST (shown with Scan Gauge II). Will be driving along and the engine "note" will change to a tone similar to that of when you are carrying out a DPF burn. The BST reads negative. It is not until you apply decent amounts of throttle that the BST goes back to a normal. I have found that when sitting at lights the the idle RPM is also about 60rpm higher than normal when this issue is happening.

Second issue is surging going up hills. I had read somewhere that this is a symptom of a SVC on its way out?

Could the two be related.

Any thoughts appreciated.

Craig.

[Goodsy]

What is the max boost you see on your scangauge? Just wondering if you have a leak in the piping to you map or a faulty MAP sensor.
And how many K's has the NS done on it's original SCV?

[pasniny]

Yep that quite normal behaviour

throttle plate closes egr opens and dpf burn is carried out.

[Craig McGoo]

Yep that quite normal behaviour

throttle plate closes egr opens and dpf burn is carried out.

Hi Pasniny, trouble is it is doing it all the time. I would have thought that there would be 200k's minimum between burns. I carried out a force Re-Gen about 1000k's ago.

As for BST indication, with hard acceleration I see 14 to 15(BST) I had to change the vaccum tubing to the MAP sensor after cleaning out the manifolds. So I will double check for leaks.

Craig.

[Stoneman]

Surging normal! Nah doubt it

I have a throttle plate installed?

Well this is another new one for me

I have never had surging during a burn

Is it doing a burn?

If not my guess is the scv get em cheap on eBay $140 posted or there about

[pasniny]

Surging normal! Nah doubt it

I have a throttle plate installed?

Well this is another new one for me

I have never had surging during a burn

Is it doing a burn?

If not my guess is the scv get em cheap on eBay $140 posted or there about

There is boost issue and surging read the post when manifold goes into vacuum at -10 PSI ecu has triggered a burn.

[pasniny]

If manifold is on vacuum all the time it could be that temp sensor 3 has failed and your car is stuck doing a burn

Check the sensor resistance. You will need a mutt to look at temp reading if temp stay below 600c during a dpf burn it will never complete.

[Stoneman]

If manifold is on vacuum all the time it could be that temp sensor 3 has failed and your car is stuck doing a burn

Check the sensor resistance. You will need a mutt to look at temp reading if temp stay below 600c during a dpf burn it will never complete.

He has a mutt and new DPF temp sensor was changed a while ago on his last thread

Its completed a forced regen so temp sensor should be ok!

Im not sure if temp sensor initialization was done.

But you probably know better

Do you have a EGR blank plate installed Craig?

[Stoneman]

here is the SCV I purchased a while ago he is a little dearer now but you can make an offer and he gives quick replies

http://www.ebay.com.au/itm/121249470036?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

I think for the mark up on these things it could be worth buying half a dozen from alibaba can get cheap from sellers on there.